Exothermic compositions constituting oxidizable metals, such as iron powder and the like, carbon components, and water, which produce heat by an oxidation reaction of an oxidizable metal, are known as, for example, those described in Patent Documents 1 and 2.
Patent Document 1 describes an ink-like or cream-like exothermic composition. It is described therein that the use of this exothermic composition prevents the generation of dust during the production of the heating element and suppresses the exothermic reaction of the exothermic composition, so that loss due to the exothermic reaction during the production, deterioration in the quality of the exothermic composition and/or solidification can be prevented.
Patent Document 2 describes an exothermic composition, having enhanced formability and shape retention ability and also having exothermic characteristics by establishing the particle diameter of the solid component of the exothermic composition and the excessive water within appropriate ranges, in which a heat-generating reaction can be started by coming in contact with air immediately after forming, and a heating element employing the same.